net.sf.saxon.expr.instruct

Class CallTemplate

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.instruct.Instruction

net.sf.saxon.expr.instruct.CallTemplate

All Implemented Interfaces:

SourceLocator, ComponentInvocation, ITemplateCall, TailCallReturner, IdentityComparable, InstructionInfo

public class CallTemplate
extends Instruction
implements ITemplateCall, ComponentInvocation

Instruction representing an xsl:call-template element in the stylesheet.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CallTemplate.CallTemplatePackage A CallTemplatePackage is an object that encapsulates the name of a template to be called, the parameters to be supplied, and the execution context.

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
CallTemplate(Template template, boolean useTailRecursion) Construct a CallTemplate instruction.

Method Summary

Methods

Modifier and Type	Method and Description
int	computeCardinality() Get the cardinality of the sequence returned by evaluating this instruction
Expression	copy() Copy an expression.
boolean	createsNewNodes() Determine whether this instruction creates new nodes.
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
WithParam[]	getActualParams() Get the actual parameters passed to the called template
int	getBindingSlot() Get the binding slot to be used.
ExpressionCompiler	getExpressionCompiler() Return the compiler of the CallTemplate expression
int	getInstructionNameCode() Return the name of this instruction.
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
ItemType	getItemType() Get the item type of the items returned by evaluating this instruction
StructuredQName	getObjectName() Get a name identifying the object of the expression, for example a function name, template name, variable name, key name, element name, etc.
protected StreamingAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
SymbolicName	getSymbolicName() Get the symbolic name of the template being called.
Component	getTarget()
Template	getTargetTemplate() Get the target template
WithParam[]	getTunnelParams() Get the tunnel parameters passed to the called template
Iterable<Operand>	operands() Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.
Expression	optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Perform optimisation of an expression and its subexpressions.
void	process(XPathContext context) Process this instruction, without leaving any tail calls.
TailCall	processLeavingTail(XPathContext context) Process this instruction.
protected void	promoteInst(PromotionOffer offer) Handle promotion offers, that is, non-local tree rewrites.
boolean	replaceOperand(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
void	setActualParameters(WithParam[] actualParams, WithParam[] tunnelParams) Set the actual parameters on the call
void	setBindingSlot(int slot) Set the binding slot to be used.
Expression	simplify(ExpressionVisitor visitor) Simplify an expression.
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Perform type checking of an expression and its subexpressions.
boolean	usesTailRecursion() Ask whether this is a tail call

Methods inherited from class net.sf.saxon.expr.instruct.Instruction

assembleParams, assembleTunnelParams, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, iterate, promote, toStreamingPattern

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getContainer, getDependencies, getEvaluationMethod, getHostLanguage, getIntegerBounds, getLineNumber, getLocationId, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeError, unordered

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Constructor Detail

CallTemplate

public CallTemplate(Template template,
            boolean useTailRecursion)

Construct a CallTemplate instruction.

Parameters:

template - the Template object identifying the template to be called, in the normal case where this is known statically

useTailRecursion - true if the call is potentially tail recursive where the name of the called template is to be calculated dynamically

Method Detail

setActualParameters

public void setActualParameters(WithParam[] actualParams,
                       WithParam[] tunnelParams)

Set the actual parameters on the call

Parameters:

actualParams - the parameters that are not tunnel parameters

tunnelParams - the tunnel parameters

getSymbolicName

public SymbolicName getSymbolicName()

Get the symbolic name of the template being called. This is essentially the component kind (template) plus the QName of the target template

Specified by:

getSymbolicName in interface ComponentInvocation

Returns:

the symbolic name of the target template

getTarget

public Component getTarget()

getActualParams

public WithParam[] getActualParams()

Get the actual parameters passed to the called template

Specified by:

getActualParams in interface ITemplateCall

Returns:

the non-tunnel parameters

getTunnelParams

public WithParam[] getTunnelParams()

Get the tunnel parameters passed to the called template

Specified by:

getTunnelParams in interface ITemplateCall

Returns:

the tunnel parameters

getTargetTemplate

public Template getTargetTemplate()

Get the target template

Returns:

the target template

usesTailRecursion

public boolean usesTailRecursion()

Ask whether this is a tail call

Returns:

true if this is a tail call

getInstructionNameCode

public int getInstructionNameCode()

Return the name of this instruction.

Overrides:

getInstructionNameCode in class Instruction

Returns:

a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

setBindingSlot

public void setBindingSlot(int slot)

Set the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target template is to be found. The target template is not held directly in the CallTemplate instruction itself because it can be overridden in a using package.

Specified by:

setBindingSlot in interface ComponentInvocation

Parameters:

slot - the offset in the binding vector of the containing package where the target template can be found.

getBindingSlot

public int getBindingSlot()

Get the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target template is to be found.

Specified by:

getBindingSlot in interface ComponentInvocation

Returns:

the offset in the binding vector of the containing package where the target template can be found.

simplify

public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException

Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression).

Overrides:

simplify in class Expression

Parameters:

visitor - an expression visitor

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                   ContextItemStaticInfo contextInfo)
                     throws XPathException

Description copied from class: Expression

Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

Overrides:

typeCheck in class Expression

Parameters:

visitor - an expression visitor

contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

optimize

public Expression optimize(ExpressionVisitor visitor,
                  ContextItemStaticInfo contextItemType)
                    throws XPathException

Description copied from class: Expression

Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:

optimize in class Expression

Parameters:

visitor - an expression visitor

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten if appropriate to optimize execution

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

computeCardinality

public int computeCardinality()

Get the cardinality of the sequence returned by evaluating this instruction

Overrides:

computeCardinality in class Instruction

Returns:

the static cardinality

getItemType

public ItemType getItemType()

Get the item type of the items returned by evaluating this instruction

Overrides:

getItemType in class Instruction

Returns:

the static item type of the instruction

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Returns:

the copy of the original expression

getIntrinsicDependencies

public int getIntrinsicDependencies()

Description copied from class: Expression

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

createsNewNodes

public final boolean createsNewNodes()

Determine whether this instruction creates new nodes. This implementation currently returns true unconditionally.

Overrides:

createsNewNodes in class Instruction

Returns:

true if the instruction creates new nodes (or if it can't be proved that it doesn't)

operands

public Iterable<Operand> operands()

Description copied from class: Expression

Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()

If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

Overrides:

operands in class Expression

Returns:

an iterator containing the sub-expressions of this expression

replaceOperand

public boolean replaceOperand(Expression original,
                     Expression replacement)

Replace one subexpression by a replacement subexpression

Overrides:

replaceOperand in class Expression

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

promoteInst

protected void promoteInst(PromotionOffer offer)
                    throws XPathException

Handle promotion offers, that is, non-local tree rewrites.

Overrides:

promoteInst in class Instruction

Parameters:

offer - The type of rewrite being offered

Throws:

XPathException

process

public void process(XPathContext context)
             throws XPathException

Process this instruction, without leaving any tail calls.

Overrides:

process in class Instruction

Parameters:

context - the dynamic context for this transformation

Throws:

XPathException - if a dynamic error occurs

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Process this instruction. If the called template contains a tail call (which may be an xsl:call-template of xsl:apply-templates instruction) then the tail call will not actually be evaluated, but will be returned in a TailCall object for the caller to execute.

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - the dynamic context for this transformation

Returns:

an object containing information about the tail call to be executed by the caller. Returns null if there is no tail call.

Throws:

XPathException - if a dynamic error occurs during the evaluation of the instruction

getObjectName

public StructuredQName getObjectName()

Description copied from interface: InstructionInfo

Get a name identifying the object of the expression, for example a function name, template name, variable name, key name, element name, etc. This is used only where the name is known statically.

Specified by:

getObjectName in interface InstructionInfo

Overrides:

getObjectName in class Expression

Returns:

the QName of the object declared or manipulated by this instruction or expression

explain

public void explain(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

explain in class Expression

Parameters:

out - the expression presenter used to display the structure

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the CallTemplate expression

Overrides:

getExpressionCompiler in class Expression

Returns:

the relevant ExpressionCompiler

getStreamingAdjunct

protected StreamingAdjunct getStreamingAdjunct()

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class Expression

Returns:

the relevant StreamingAdjunct, or null if none is available